1. Field of the Invention
This invention pertains generally to closure fasteners, and more particularly to keepers in which a bolt or latch receiving socket is provided with a movable cover. A preferred manifestation of the invention is a door latch blocker coupled by a hinge to a strike plate. The latch blocker pivots about the hinge to selectively cover the keeper, and thereby block the door bolt, or pivot away from and expose the keeper, to allow the door bolt to engage with the keeper. In one manifestation, the assembly is reversible to replace standard strike plates and accommodate left and right-handed doors that open in or out.
2. Description of the Related Art
Buildings and other similar static structures have openings, sometimes referred to as portals, that provide access to and from interior spaces within the building. These portals are ordinarily controlled by a moving door or window that can be opened or closed. Doors may be found in the exterior walls of the building, in which case they may be sealed against the elements when closed, and may also typically be secured to allow the building to be locked when desired. Similarly, interior doors control portals in the building interior, for exemplary and non-limiting purposes only such as between a room and a hallway. These interior doors are not usually exposed to the elements, but may in many cases be provided with some type of lock allowing the individual room to be secured, even when access to the hallways is still being provided through the exterior doors.
Many doors designed primarily for use by people consist of a panel that swings on hinges. These doors typically have one or several hinges mounted on one vertical edge of the door panel that are anchored to the door jamb. On the other vertical edge of the door panel a retractable bolt may protrude. The retractable bolt is selectively inserted into an opening in the door jamb referred to as a keeper. When the retractable bolt extends into the keeper, the door is latched closed. When the retractable bolt is retracted from the keeper, the door is free to swing open. Most doors are prevented from swinging from one side of the frame on through the door jamb and out the other side by a thin slat built inside the door frame, commonly referred to as a doorstop. There is a strike plate provided with a gentle slope, such that when the door is pivoting towards the doorstop with spring-loaded bolt protruding from the door edge, the bolt will engage with the strike plate and gradually be retracted into the door as the door continues to swing shut. Eventually as the door continues to rotate closed, the door will swing into engagement with the doorstop, and at this position the spring-loaded bolt will push into the opening defined by the keeper. With the bolt engaged in the keeper, the door is held shut.
Doors can serve many functions, among them the control of passage of people and animals through the portal. This means the door can be used to selectively keep people either in or out of a building space. The door can also act as a barrier to movement of air, which can be critical in heating, ventilation and air conditioning (HVAC); in limiting noise transmission; and in limiting the spread of a fire. For many applications, it is desirable to enable and preserve each of these uses, to maintain full functionality of the door. This is particularly true in public buildings, where control in any other way can be extremely difficult.
Unfortunately, in public buildings, a person within a room or other space will often not have a key or other way to control the door. For exemplary purposes only, and not limiting the invention solely thereto, a school may have many students in a classroom. Ordinarily, a teacher will be present, but the teacher may also be the only person in the room to whom a key has been provided. In such instance, the primary purpose of the key is to enable the teacher to secure the classroom at the end of the school day against passage of people, thereby preventing after-hours theft or vandalism. Often times, the school building may be open long after the final class has been dismissed, such as for various extra-curricular activities including but not limited to band concerts, sporting events, and even parent-teacher conferences. To preserve the classrooms, it is desirable to lock the classroom doors at the end of the classroom day, thereby preventing intruders or vandals, while still keeping other facilities within the school open much longer.
The classroom door will also typically, but not always, be closed during classroom instruction to limit noise transmission, so that any activities taking place in the hallways are less likely to disrupt the classroom or distract the students. Between periods of classroom instruction, the door may then be opened up to allow the students to pass through and on to their next assigned classroom.
In the event of a fire, gas leak, hazardous chemical release, or other similar emergency, a door may also be used to contain the fire or gas to a particular room or building space. In many of these cases, the building occupants will be escorted through the building halls, preferably away from the quarantined area, and out of the building to a safe location. However, if safe passage out of the building is not immediately possible, the door will also preferably provide a barrier to the movement of the fire or noxious gases into the classroom, allowing the occupants greater time within which to be rescued.
While historically fire was one of the greatest hazards to building occupants, more recently many public buildings have been constructed of concrete, steel and other similar fire resistant materials. While fire has not and likely never will be completely eliminated as a hazard, a new hazard has arisen that has drawn much media attention.
Public spaces naturally have a high concentration of people during ordinary hours of operation. Exemplary public spaces include, but are not solely limited to schools, governmental buildings, apartment buildings, and many office buildings. Communities depend upon these public spaces being safe. Unfortunately, with the concentrations of people, an intruder who wishes to bring harm in such spaces can present a very real and substantial hazard to many people.
One way to slow or block the intruder from accessing the people in a community space is by using a door to also control or limit the access that such an intruder may have into these spaces. This can be quite beneficial for security, since a person intruding upon a space can be stopped or slowed by a secured door. However, as noted above, in community spaces there are usually only a few people who may have keys to lock the doors.
Protecting a space from an intruder is quite different from preventing vandalism or theft. In the case of an intruder, there will often be very little time to secure the door. Most preferably, the closest person to the door will secure the door. With many lives at stake, the excitement of the moment will in and of itself present enormous challenge. Consequently, the mechanism will preferably be as simple as possible and activated by whomever is closest, regardless of their skills or training.
There may also be circumstances where it may be desirable to provide an occupant a keyless method for quickly, selectively allowing people access through the doorway. In the case of the public spaces, once the space has been unlocked by a person with keys, people will normally move freely through the building. In another instance, when a person wishes to step out of their apartment or hotel room, perhaps to flag down a service or delivery person, they may not always remember or have ready access to the room key. Another instance might be where a number of guests will be arriving, none whom would otherwise be able to pass through an automatically locking door. Consequently, it is desirable to provide rapid and intuitive enablement to both secure a door and to alternatively release a door lock.
A number of skilled artisans have developed methods for selectively controlling a door lock. Some exemplary patents, the teachings and contents which are incorporated herein by reference, include U.S. Pat. No. 5,074,604 by Merendino et al, entitled “Door knob and latch retaining device”; and U.S. Pat. No. 8,177,267 by Kuehn, entitled “Door anti-latch device”. The Merendino et al patent uses a traditional round rotary interior house door knob, and provides a member that frictionally engages between the rotary knob and the door, to cause the knob, and therefore the bolt, to stick in whatever position a person sets the knob to. This device may have utility with many interior house doors, but unfortunately the amount of friction will vary both between different doors and with the age of the door. Furthermore, not all door knobs are round, particularly in public buildings. The Kuehn patent discloses a device that blocks the door from closing completely, thereby preventing the bolt from ever aligning with the keeper. While this and similar door blocking devices can be very effective, the force of the door swinging shut can damage the blocking device or the door frame. Furthermore, many of the benefits that would be obtained from a closed door, such as the blocking of noises outside of a classroom for example, are lost.
Another set of artisans have devised apparatus that are attached to a door component to block the door bolt from entering into the keeper, and are then removed to inactivate bolt block. Exemplary patents, the teachings and contents which are incorporated herein by reference, include patents: U.S. Pat. No. 2,249,294 by Kohler, entitled “Device for preventing the unintentional shutting of doors”; U.S. Pat. No. 2,726,892 by Zynda et al, entitled “Safety lock clip”; U.S. Pat. No. 3,309,126 by Schuette, entitled “Child-safe door catch assembly”; U.S. Pat. No. 5,004,279 by Radcliff, entitled “Door latch holder”; U.S. Pat. No. 6,698,807 by Wacker, entitled “Latch guard”; U.S. Pat. No. 7,766,400 by Predebon, entitled “Door stay”; CH 212,832 by Kohler, entitled “Device on a door to prevent accidental slamming of the same”; and WO 8400394 by Busch, entitled “Element for preventing the closing of a door”. One of the challenges with these apparatus is how to keep or store the bolt blocking apparatus when it is not in use, and yet to ensure that the apparatus is available when needed. The Busch international patent application provides a separate plate to which the magnet may stick when the magnetic apparatus is not in place blocking the lock. Nevertheless, many of these apparatus will be easily fumbled or dropped in an emergency situation by a person of ordinary nerves. Furthermore, in a commercial or other public location even those few patents such as the Radcliff and Predebon that provide a pair of hangers from opposed knobs, these apparatus will be lost, stolen, or vandalized in short order, rendering the facility unprotected against intruders.
Another much more limited group of patents illustrate or may be adapted in light of the teachings of the present invention to be always available, selectively applied bolt blocks. Exemplary patents, the teachings and contents which are incorporated herein by reference, include patents: U.S. Pat. No. 6,082,790 by Mossotti et al, entitled “Door anti-locking device”; U.S. Pat. No. 987,271 by Upton, entitled “Attachment for door latches”; U.S. Pat. No. 2,630,005 by Raivetz, entitled “Lock bolt retainer”; U.S. Pat. No. 3,458,227 by Bryson et al, entitled “Closure Device”; U.S. Pat. No. 4,159,838 by Wilzig et al, entitled “Door latch bolt locking device”; and WO 0003108 by Micudaj, entitled “Safety device for locking elements on doors or similar”. The Mossotti et al door anti-locking device provides many desirable features, such as easy installation onto an existing strike plate, rapid actuation, and ensured presence when needed.
Unfortunately, even the Mossotti et al patent suffers from several undesirable limitations. The primary limitation is the need for precise control over the torque used to tighten the hardware that holds both the anti-locking device and the strike plate together in place in the door frame. If the screw is tightened down too much, the plate will not be free to rotate. If instead the screw is too loose, then the plate will not stay in the upright, out-of-the-way position illustrated on the front page of the patent. Furthermore, the Mossotti et al device relies upon a vertical position for the inactive state or door-locked position, a position which is not easily set or maintained. In other words, in the event of an intruder, a person may in haste swing the Mossotti et al anti-locking device hard enough for the device to bounce off of the doorstop, in which case the anti-locking device will simply pivot back down to the one stable position, which is blocking the keeper and keeping the door open. Consequently, the Mossotti et al device requires periodic maintenance to ensure that the anchoring screw is properly tightened and functioning, and, in an emergency situation, requires a person of more calm than most can be expected to have to carefully rotate and hold the device in the upright position out of the way of the keeper before closing the door.
In addition to the foregoing patents, Webster's New Universal Unabridged Dictionary, Second Edition copyright 1983, is incorporated herein by reference in entirety for the definitions of words and terms used herein.